Animals are exposed to many stresses during their lives. These stresses affect the health of the animal, the growth of the animal, and overall well-being. Currently, antibiotics and other treatments are used to improve the immune function of animals. Concerns over antibiotic use in animal production has created a need to find more natural immunostimulants.
Beta-glucans are linked polysaccharides and are a component of yeast cell walls. Beta-glucan has been reported as a dietary supplement for aiding digestion and reducing cholesterol levels in animals and humans (EP 0440725 B 1, Jun. 1, 1994). Beta-glucan has also been reported as useful for reducing weight gain or enhancing weight loss (U.S. Pat. No. 6,020,324, Feb. 1, 2000). Beta-glucan has been reported to increase the high density lipoprotein cholesterol level in mammals (U.S. Pat. No. 6,143,731, Nov. 7, 2000). Beta-glucan has been reported as a component in animal feed to enhance the growth rate of an animal (U.S. Pat. No. 6,214,337, Apr. 10, 2001). Beta-glucan has also been reported to be useful in enhancing the efficacy of a fish vaccine (U.S. Pat. No. 5,147,862, Sep. 15, 1992; U.S. Pat. No. 5,401,727, Mar. 28, 1995; U.S. Pat. No. 5,189,028, Feb. 23, 1993).
Vitamin C (ascorbic acid), an anti-oxidant, has been generally reported to stimulate immune response. The effect that vitamin C and glucan have on the immune function in fish has been studied (Fish & Shellfish Immunology (1998) 8, 409–424; Aquaculture 143 (1996) 123–133).
An improved method of strengthening the immune system and improving the well-being of animals is needed.